The present invention is directed to enabling wireless networks to serve the delivery of local loop voice, video and data services, primarily by increasing the bandwidth density of said wireless networks. More specifically, the present invention is directed to increasing the performance of wireless transmission by improvements primarily but not limited to, bandwidth density and reliability, using primarily, but not limited to, centralized control, spatial radiation control, and tiered messaging architecture. Bandwidth density is the amount of unique simultaneous traffic that can be delivered to a body of subscribers in a given geographical area.
Deregulation of the communications industry has allowed communications companies to compete in areas where they were previously prohibited from competing. This has resulted in telephone companies offering high speed data communications and television programming in addition to their traditional voice communications products. Likewise, cable companies offer voice and high speed data communications over their existing cable infrastructure. The cost of upgrading existing cable and telephone networks has been passed on to customers in the form of higher monthly bills. Cable and telephone companies can raise customers' monthly bills with little concern for losing customers because the costs a potential competitor would incur for building a new wired infrastructure to compete with existing cable and telephone companies is prohibitively expensive.
Currently wireless companies are attempting to provide a bundle of communications services over cellular networks. For example, some wireless companies are providing high speed data and video communications over their cellular networks. Providing high speed data and video communications over cellular networks requires massive upgrades to conventional voice cellular networks. Even after the massive upgrades, the actual bandwidth density achievable in these upgraded cellular networks is much lower than that of existing wired infrastructures and typically not sufficient to deliver digital television signals, digital telephone service, and high-speed internet access simultaneously to a large body of users. This is due in part to the self-interfering nature of conventional cellular networks and the fact that each cellular tower must cover a large service radius and divide up its available throughput among a large number of potential users for the cost per user to even approach acceptable levels. Because of the high cost of the upgrades and the limited bandwidth density provided by the cellular architectural model, high speed wireless data and video communications are used mostly by business users, as they are the ones with the ability to pay the high bills associated with such services.
Existing cellular networks are based on a point-to-multi-point communications model. Specifically, a base station (i.e., the point) serves a number of mobile stations (i.e., the multi-point) in a particular cell. The bandwidth that can be provided by a particular cell is limited, and must be divided among all of the mobile stations in a particular cell. Accordingly, the more mobile stations in a particular cell, the less amount of bandwidth which can be allocated to a particular mobile station. Additionally, each cell in a cellular network produces interference to other proximately located cells in the network, and each mobile station produces interference to other mobile stations. This cell-to-cell interference is typically mitigated by using different frequency assignments for adjacent cells further increasing the cost and complexity of using the cellular model.
The potentially large distances between a cell tower and a mobile station can result in numerous obstacles and sources of interference which can limit or eliminate the throughput between the tower and the mobile station. This makes the certainty and the speed of a connection unpredictable and unreliable especially for mobile stations that are located a significant distance from the central tower. All of these factors further reduce the total bandwidth which can be provided by a base station in a particular cell especially on the return path when a mobile station is sending to a cell tower. For these reasons most consumer services are configured as asymmetrical services in which much less bandwidth is provided upstream than downstream toward the user.
Others have attempted to overcome the bandwidth density limitations of point-to-multipoint wireless architectures by designing so-called mesh architectures. With these designs many low power radio transceivers are placed in proximity to each other such that each radio's signal can be received by a plurality of other radios. The radios are each equipped with store-and-forward routing capability such that each radio that receives a packet of traffic can at some point forward it to another radio which forwards it in turn to its eventual destination.
One problem of typical mesh architecture is that any radio that wishes to send must wait until all other radios in the mesh network within its range are not sending. This results in most radios in a large mesh network being in a waiting-to-send state more than a sending state. The large amount of time in the waiting-to-send state severely reduces average throughput for each node in the network and results in poor overall bandwidth density performance for the network as a whole. Attempts have been made to mitigate the self interference and increase the practical distances between nodes in mesh networks by equipping each node in the mesh with multiple directional antennas and physically aiming those antennas at specific other nodes in the network. Although this can improve mesh network performance it is costly and operationally complex to physically aim and re-aim the antennas as nodes are added and deleted from the network and changing environmental conditions affect the throughput performance between individual nodes.